Polyurethane and polyisocyanurate rigid foams prepared using ternary blowing agent mixtures

Abstract

Use of a ternary blowing agent mixture containing water, HCFC-22, and either or both of methylene chloride or 1,1,1-trichloroethane allows the preparation of rigid urethane and polyisocyanurate foams displaying good dimensional stability and low aged k-factors.

What is claimed is: 
     
       1. A dimensionally stable, low k-factor polyurethane or polyisocyanurate rigid foam having a density from about 1.3 to about 3.0 lbs/ft 3 , containing in its cells carbon dioxide, monochlorodifluoromethane, and a third blowing agent component selected from the group consisting of methylene chloride, 1,1,1-trichloroethane, and mixtures thereof. 
     
     
       2. The foam of claim 1 wherein the density of said foam is greater than about 1.6 pounds/ft 3 . 
     
     
       3. A rigid foam, prepared by the process of reacting a) an organic isocyanate;   b) an isocyanate reactive component comprising one or more polyols selected from the group consisting of polyoxyalkylene polyether polyols, polyester polyols, and mixtures thereof;   c) an effective amount of one or more catalysts which promote the formation of urethane and/or isocyanurate linkages; and   d) a ternary blowing agent mixture comprising i) water,   ii) monochlorodifluoromethane, and   iii) a third blowing agent component selected from the group consisting of methylene chloride, 1,1,1,-trichloroethane, and mixtures thereof, at an isocyanate index of from 70 to about 900.       
     
     
       4. The foam of claim 3 wherein said ternary blowing agent comprises i) amount of from 1 to about 10 percent by weight;   ii) HCFC-22 in an amount of from 1 to about 20 percent by weight;   iii) from 1 to about 20 percent by weight of a third blowing agent component selected from the group consisting of methylene chloride, 1,1,1-trichloroethane, and mixtures thereof, wherein all said percents by weight are percents by weight relative to the weight of component b).     
     
     
       5. The foam of claim 3 wherein said ternary blowing agent comprises i) in an amount of from 1 to about 7 weight percent;   ii) HCFC-22 in an amount of from 4 to about 8 weight percent; and   iii) from 5 to about 15 weight percent of a blowing agent component selected from the group consisting of methylene chloride, 1,1,1,-trichloroethane, and mixtures thereof. wherein said weight percents are weight percents relative to the weight of component b).     
     
     
       6. The foam of claim 3 wherein the density of said foam is from about 1.6 pounds/ft 3  to about 3 pounds/ft 3 . 
     
     
       7. The foam of claim 4 wherein the density of said foam is from about 1.6 pounds/ft 3  to about 3 pounds/ft 3 . 
     
     
       8. The foam of claim 5 wherein the density of said foam is from about 1.6 pounds/ft 3  to about 3 pounds/ft 3 . 
     
     
       9. In a process for the preparation of a rigid foam containing urethane and/or isocyanurate linkages by the reaction of a polyol component with an isocyanate component, the improvement comprising selecting as a blowing agent for said foam a ternary blowing agent comprising i) water in an amount of from 0.1 to about 10 weight percent;   ii) monochlorodifluoromethane in an amount of from about 1 to about 20 weight percent; and   iii) a third blowing agent component selected from the group consisting of methylene chloride, 1,1,1-trichloroethane, and mixtures thereof in an amount of from 1 to about 20 weight percent, wherein all said weight percents are based on the weight of the polyol component.     
     
     
       10. The process of claim 9 wherein water is present in an amount of from 1 to about 7 weight percent: monochlorodifluoromethane is present in an amount of from 1 to about 8 weight percent; and said third blowing agent component is present in an amount of from 5 to about 15 weight percent, wherein said foam has a density of greater than 1.6 pounds/ft 3 .